Air brush



Jam 6, Mll.

l.y LARSON AIR BRUSH Filed Sept. 22, 1927 2 Sheets-Sheet l Jan le, 1931. L. LARSON 1,787,583

AIR BRUSH Filed Sept. 22, 192'? 2 Sheets-Shes?a 2 gun adapted to apply Patented Jan. 6, 1931 UNITED 's'rA'rl-:s

PATENT OFFICE .un snoei! Application med September 22, 1927. Serial Ro. 821,848.

(GRANTED UNDER THE ACT F MARCH 3, 1883, AS AMENDED APRIL 30, 1928; 370 0.A G. 757) The invention described herein may be used by the Government, or any of its oiiicers or employees in prosecution of work for the Government, or by any other person in the United States, without payment to me of any royalty thereon.

Thls inventionrelates to improved apparatus for applying liquids to surfaces by means of air pressure, and particularly to an apparatus known as an air brush or paint aint or other liquids to a surface by means o a stream of air under pressure.

The objects of the invention are the provision of a device of the above character, in which the controlling means for the flow of paint and air are convenient to the operator, are of simple construction, may be readily separated for cleaning purposes, and may be economically manufactured.

A further object is to provide a construction wherein, not only the flow of air and liquid are separately controlled, but provision is made whereby the relative lifting power or vacuum created by a given current of air flowing through the air jet, may be increased or diminished, thereb providing for the variations in viscosity o the Huid to be lifted and atomized.

Similar numerals indicate corresponding the invention, such disclosed means constituting, however, one of the various forms in which the principle of the invention may be used.

Fig. 1 is a view showing the improved air brush and its attachments.

Fig-2 is an enlarged longitudinal section ofthe air brush.

Fig. 3 is a detail elevation of the air jet, showing its interior, outlined in dots.

Fig. 4 is a similar view of the adjustable nipple.

Fig. 5 is a detail side view with parts dotted, showing the body portion wlthout attachments.

Reference now being had to the drawings by numerals, 6 represents the surface to be painted, 7 the paint gun or air brush, 8 the source of iuid pressure supply shown diagrammatically, 9 the paint or other li uid supply container and 10 and 11 flexible uid and 1i uid supply pipes or tubes, respectively.

Wit special re erence to Fig. 2, it will be seen that the air brush, consists of the hollow main body portion 12, having a lateral extension 13 approximately centrally located, said extension being internally threaded, in which the fluid supply cut-oft` valveV 14 in the paint line is mounted.

The body ortion l2, is provided with a vacuum cham er 15 with which the liquid inlet communicates and is at its ends internally screw threaded, as shown at 16 and 17.

Into opening 16, is` threaded an adjustable nipple 18, said nipple being provided with the outlet opening 19 and a concave outer face 20 surrounding the opening, the latter aiding in the diiusionv of the spray. The interior of the adjustable nipple 18, directly back of the opening 19, is abru tly tapered to l a large bore or cavity 21 whic is in connection with and forms a. part of the vacuum chamber 15. v

. The vacuum chamber 15 is located in the body portion, into which the air jet nozzle projects.

The air jet member 22, consists of a rear or outer portion 23, preferably of the same outer dimensions as the body portion 12, having an exterially screw threaded ortion 24 adapted to enter the body 12. X tapered nozzle 25 extends from the threaded portion 24, and enters the vacuum chamber when the parts are assembled. Said vacuum chamber consists of the space surrounding the nozzle 25, and the cavity 21 within the nipple, which is in communication with the lateral liquid inlet passage. The bore of the air jet member is tapered toward its outlet end and terminates in a small'opening, surrounding said opening in the end of the nozzle, is a cut back or dish shaped portion 26 adapted to spread the blast` of air, said formation of the nozzle, and the nipple at their outlets being for the purpose of producing a perfect mixture of air and liquid to form a vapor.

In the arrangement of the parts as shown,

a cut-0E valve 27 is provided in the air line adjacent to the jet member, whereby the operator may have convenient control of the flow of air.

In operation it has been found that at times aconstant intensity of air blast or other f imd is desired, but, due to the various viscosltics of the paint or other liquids to be lifted, the power of the blast of air must be increased to overcome the greater weight or sluggishness of the li uid.

It is o vious that a jet of air required to lift by vacuum and properly atomize a liquid such as a `wall sizing or other thin solution of low viscosity, will not under the same conditions be suliicient to lift and atomize a heavy paint or varnish, and it is by providing lneans whereby the capacityof the air blast may be controlled, that the lifting and atomizing of liquids of diferent densities, with a jet of constant volume and velocity, is accomplished.

The parts above described provide forthe diminishing or increasing of the capacity of the vacuum chamber and the distance between the nipple orifice, and the discharge opening of the ai-r jet nozzle. y

The adjustments referred to are both accomplished simultaneously by the adjustment of the nipple 18. By moving the nipple inwardly, the capacity of the vacuum chamber is reduced, and the nozzle discharge opening is brought closer to the nipple discharge opening, thus increasing the lifting power of the airjet and intensifying atomization, the two combining to compensate for a heavier demand due to the thicker and denser liquids to be lifted, atomized and discharged against the surface to be treated.

By reference to Fig. 5 the extreme simplicity ofthe device may be better understood and consists of a body portion or Thead having a centrally located lateral extension, each bored to intersect and tapped. Into one end' of the head the nipple of simple construction is threaded, into the other the air jet of simple construction is threaded, said simple and inexpensive parts when connected by stock valves and flexible tubing, to air and liquid sources, provide an air brush or paint gun that has by extensive use proved to be a construction of great efficiency and economy.

l Vlhat is claimed anddesired to be secured by Letters vPatentjis':

`1. A device of the class described consistingof a body portion, having a threaded axial bore, a lateral extension having a threaded axial bore in communication-with said first mentioned bore, an air jet member threaded into the body portion from one end and a nipple having' a restricted portion in itsbore and adapted to be-threaded into the body portion at its opposite end for adjustment to and from said air jet, said parts when assembled, adapted to provide a vacuum chamber in the body portion of variable sizes, for increasing or diminishing the lifting power of the air blast.

2. A device of the class described consisting of a body portion, having a threaded axial bore, a lateral extension having a threaded axial bore in communication with said first mentioned bore, an air jet having an enlarged outer end threaded into the body portion and having a nozzle extending approximately to the opposite end of the body portion, an adjustable nipple mounted in said opposite end of the body portion provided with a bore having a restricted portion into which said air nozzle extends, said parts when assembled adapted to provide a vacuum chamber in the body portion of variable size for ,increasing or diminishing the lifting powej-of the air blast.

vacuum chamber within the body portion of variable size, for increasing or diminishing the lifting power of the air blast.

n 4. A device of the class described consisting of a body portion, having a threaded axial bore, a lateral extension having a threaded axial bore in communication with said first mentioned bore, an air jet member entering the body portion from one end provided with an enlarged rear end, an intermediate screw threaded portion, and a reduced nozzle portion having a tapered bore and a flared discharge opening, thev latter extending approximately entirely through the body ortin, and a nipple having a restricted o emng and flared portion inside and outside o said open ing mounted in the opposite end of the body portion and adapted to be adjusted to and from the air jet nozzle for increasing or diminishing the power of the air blast, means forconveying liquid to the lateral extension nipple mounted in the opposite end of the other end of the body portion .adapted to body portion, provided with a restricted control the ow of. mixture or fluid and portion and a flared discharge orilice, adaptliquid from the device and means for suped for adjustment to increase and diminish plying Huid and liquid to sald valves.

the distance between the discharge orifice of LEANDER LARSON. the nozzle and the discharge opening of the nipple, to increase or diminish the lifting power of the air blast.

6. A device of the class described consisting of a body portion, having an axial bore, a lateral extension having an axial bore in communication with' said first mentioned bore, an air jet member having a discharge opening mounted in the body portion at one end, having a screw threaded portion litting the bore of the body member and a reduced vnozzle portion of a diameter less than that of the bore of the body portion to provide a vacuum chamber adjacent to the axial bore of the lateral extension, a nipple having a restricted passage and a flared discharge opening mounted in the opposite end of the bore of the body portionand adapted to be adjusted in relation to the nozzle to increase and diminish the capacity of the vacuum chamber and the relative positions of the discharge end of the air nozzle and the discharge opening of the nipple to increase and diminish the lifting power of the air blast, and means for conveying liquid to the bore of the lateral extension, means for conveying fluid under pressure to the air jet member, and mea-ns for controlling said flow of liquid and Huid.

7. A device of the class described consisting of a body portion having a threaded bore and a lateral extension having a threaded bore in communication with said lirst mentioned bore, a valve mounted in the lateral extension adapted to control the flow of liquid to thedevice, a fluid pressure jet having a tapered bore and a ared dischargek and threaded into and rigidly mounted in one end of the body portion, a valve mounted in the jet adapted to control the flow of fluid to the device, a discharge nipple, having a restricted bore, adjustably threaded into the other end of the body portion adapted to control the ow of mixture of fluid and liquid from the device and means for supplying Huid and liquid to said valves.

8. A device of the class described consisting of a body portion having a threaded bore and a lateral extension having a threaded bore in communication with said first mentioned bore, means for controlling the flow of liquid to the device through said extension, a Huid pressure jet having a tapered bore and .a iared discharge an d threaded into and rigidly mounted in one end of the body portion,- mea-ns for controlling the flow of uid to the device throughk said jet, a discharge nipple, having a restricted bore, adjustably threaded into the 

